Bagged salad: How clean?

You might think that "pre­washed" and "triple-washed" salad greens sold in plastic clamshells or bags are squeaky clean. But
our recent tests found room for improvement.

No, we didn't find pathogens such asE. coli O157:H7, listeria, or salmonella. With our small sample size—208 containers representing 16 brands purchased at stores
in Connecticut, New Jersey, and New York—we didn't expect to. (The Department of Agriculture, in a test of more than 4,000
samples of loose and packaged salad in 2008, found salmonella in two of them. All of our tests included packaged greens.)

But in our samples, all of which were within their use-by date, we did find bacteria that are common indicators of poor sanitation
and fecal contamination—in some cases, at rather high levels.

We tested for total coliforms and for other bacteria, including enterococcus, that are better indicators of fecal contamination.
Federal action limits exist for indicator organisms in water, raw meat, milk, and some processed foods, but not produce. Those
organisms are typically used to gauge possible pathogen contamination.

Several industry experts we consulted suggested that for leafy greens, an unacceptable level of total coliforms or enterococcus
is 10,000 or more colony forming units per gram (CFU/g) or a comparable estimate. In our tests, 39 percent of samples exceeded
that level for total coliforms and 23 percent for enterococcus.

Results varied widely among samples, even within the same brand, from undetectable levels of those bacteria to more than 1
million CFU/g. Packages with higher bacteria levels had similarities. Many contained spinach and were one to five days from
their use-by date. Packages six to eight days from their use-by date fared better. Whether the greens came in a clamshell
or bag, included "baby" greens, or were organic made no difference.

Brands for which we had more than four samples, including national brands Dole, Earthbound Farm Organic, and Fresh Express,
plus regional and store brands, had at least one package with relatively high levels of total coliforms or enterococcus. Our
tests were conducted at an outside lab over two weeks in August and September with financial support from the Pew Health Group,
which is working to improve food safety.

Consumers Union supports Senate Bill 510, the Food Safety Modernization Act, that would, among other things, require the Food
and Drug Administration to set stronger produce safety standards. Those should include performance standards for indicators
of fecal contamination, such as generic E. coli and enterococcus.

What you can do

Buy packages as far from their use-by date as you can find.

Even if the bag says "prewashed" or "triple-washed," wash the greens yourself. Rinsing won't remove all bacteria but may remove
residual soil.